Multi charged particle beam writing apparatus and multi charged particle beam writing method

ABSTRACT

A multi charged particle beam writing apparatus according to one aspect of the present invention includes a plurality of first blankers to respectively perform blanking deflection of a corresponding beam in multiple beams having passed through the plurality of openings of the aperture member, a plurality of second blankers to deflect a defective beam in the multiple beams having passed through the plurality of openings of the aperture member to be in a direction orthogonal to a deflection direction of the plurality of first blankers, a blanking aperture member to block each of beams which were deflected to be in a beam off state by at least one of the plurality of first blankers and the plurality of second blankers, and a detection processing unit to detect a defective beam in the multiple beams having passed through the plurality of openings of the aperture member.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No.13/770,322, filed on Feb. 19, 2013, which is based upon and claims thebenefit of priority from Japanese Patent Application No. 2012-065388filed on Mar. 22, 2012 in Japan, the entire contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a multi charged particle beam writingapparatus and a multi charged particle beam writing method. For example,the present invention relates to a method for achieving high accuracy inwriting with multiple beams.

2. Description of Related Art

The lithography technique that advances microminiaturization ofsemiconductor devices is extremely important as being a unique processwhereby patterns are formed in the semiconductor manufacturing. Inrecent years, with high integration of LSI, the line width (criticaldimension) required for semiconductor device circuits is decreasing yearby year. The electron beam (EB) writing technique, which intrinsicallyhas excellent resolution, is used for writing or “drawing” a pattern ona wafer, etc. with an electron beam.

As an example using the electron beam writing technique, there is awriting apparatus using multiple beams (multi-beams). Since it ispossible for a multi-beam writing apparatus to perform irradiation withmultiple beams at a time, throughput can be greatly increased comparedwith the case of writing using a single electron beam. In such a writingapparatus of a multi-beam system, for example, multiple beams are formedby letting an electron beam emitted from an electron gun assembly passthrough a mask with a plurality of holes, blanking control is performedfor each beam, and each of unblocked beams is reduced by an opticalsystem and deflected by a deflector so as to irradiate a desiredposition on a target object or “sample” (refer to, e.g., Japanese PatentApplication Laid-open (JP-A) No. 2006-261342).

In such a writing apparatus of the multi-beam system, irradiation of aplurality of beams is performed at a time, and a pattern is written bycombining “beam on” and “beam off” by blanking control as describedabove. Regarding the writing apparatus of the multi-beam system, thereis a concern about yield (generation of a defective beam) because ofstructural complexity for forming and controlling a plurality of beams.For example, when the beam-off control cannot be performed, a defectivebeam being continuously “beam on” may be generated. In addition, thereis a case of generating a defective beam which does not have a specifiedamount of beam current or whose dose cannot be controlled within apredetermined irradiation time period even if the beam-off control canbe performed. When a defective beam of this kind exists, a problemoccurs in that a desired pattern is not written or desired writingaccuracy is not obtained even though writing is performed.

BRIEF SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, a multi chargedparticle beam writing apparatus includes a stage configured to mount atarget object thereon and be movable continuously, an emission unitconfigured to emit a charged particle beam, an aperture member, in whicha plurality of openings are formed, configured to form multiple beams byletting a region including a whole of the plurality of openings beirradiated by the charged particle beam and letting parts of the chargedparticle beam respectively pass through a corresponding opening of theplurality of openings, a plurality of first blankers configured torespectively perform blanking deflection of a corresponding beam inmultiple beams having passed through the plurality of openings of theaperture member, a plurality of second blankers configured to deflect adefective beam in the multiple beams having passed through the pluralityof openings of the aperture member to be in direction orthogonal to adeflection direction of the plurality of first blankers, a blankingaperture member configured to block each of beams which were deflectedto be in a beam off state by at least one of the plurality of firstblankers and the plurality of second blankers, and a detectionprocessing unit configured to detect a defective beam in the multiplebeams having passed through the plurality of openings of the aperturemember.

In accordance with another aspect of the present invention, a multicharged particle beam writing method includes detecting a defective beamin multiple beams having passed through a plurality of openings of anaperture member in which the plurality of openings are formed to formmultiple beams by irradiation of a charged particle beam, and performingmultiple writing while executing position shifting such that positionsof defective beams in the multiple writing are not located at a sameposition, by using at least one of remaining multiple beams in a statewhere the defective beam has been controlled to be beam off.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a configuration of a writingapparatus according to Embodiment 1;

FIGS. 2A and 2B are schematic diagrams each showing a configuration ofan aperture member according to Embodiment 1;

FIGS. 3A and 3B are schematic diagrams each showing a cross-sectionalstructure of a blanking plate according to Embodiment 1;

FIG. 4A shows a part of the upper surface of a blanking plate accordingto Embodiment 1;

FIG. 4B shows a part of the under surface of a blanking plate accordingto Embodiment 1;

FIGS. 5A to 5C are schematic diagrams explaining a writing operationaccording to Embodiment 1;

FIG. 6 is a flowchart showing main steps of a writing method accordingto Embodiment 1;

FIG. 7 is a schematic diagram showing an unused beam according toEmbodiment 1; and

FIGS. 8A and 8B are schematic diagrams explaining a method of multiplewriting according to Embodiment 1.

FIG. 9 is a schematic diagram showing a mechanical switch in a relaycircuit according to Embodiment 1.

DETAILED DESCRIPTION OF THE INVENTION Embodiment 1

In the following Embodiment, there will be described a structure inwhich an electron beam is used as an example of a charged particle beam.The charged particle beam is not limited to the electron beam, and othercharged particle beam, such as an ion beam, may also be used.

Moreover, in the following Embodiment, there will be described anapparatus and method capable of certainly eliminating a defective beamwhich is always continuously “beam on” because the beam-off controlcannot be performed or a defective beam whose dose cannot be controlledwithin a predetermined irradiation time period, in a multi beam writingsystem.

FIG. 1 is a schematic diagram showing a configuration of a writingapparatus according to Embodiment 1. In FIG. 1, a writing (or “drawing”)apparatus 100 includes a writing unit 150 and a control unit 160. Thewriting apparatus 100 is an example of a multi charged particle beamwriting apparatus. The writing unit 150 includes an electron lens barrel102 and a writing chamber 103. In the electron lens barrel 102, thereare arranged an electron gun assembly 201, an illumination lens 202, anaperture member 203, a blanking plate 214, a reducing lens 205, alimiting aperture member 206, an objective lens 207, and a deflector208. In the writing chamber 103, there is arranged an XY stage 105, onwhich a target object or “sample” 101 such as a mask serving as awriting target substrate is placed when performing writing. The targetobject 101 is, for example, an exposure mask used for manufacturingsemiconductor devices, or a semiconductor substrate (silicon wafer) onwhich semiconductor elements are formed. The target object 101 may be,for example, a mask blank on which resist is applied and a pattern hasnot yet been formed. On the XY stage 105, further, there are arranged aFaraday cup 106 as an example of a current amount measurement unit, anda mirror 210 for measuring a position of the XY stage 105. Moreover, onthe upper surface of the blanking plate 214, a plurality of blankers 212(second blanker) for cutting a defective beam are arranged, and on theunder surface, a plurality of blankers 204 (first blanker) forperforming blanking deflection are arranged.

The controlling unit 160 includes a control computer 110, a memory 112,a constant voltage source 120, a relay circuit 122, blanking controlcircuits 130, deflection control circuits 132, blanking amplifier 134,digital-to-analog converter (DAC) amplifiers 136, a current detector138, a stage position measurement unit 139, and a storage device 140such as a magnetic disk drive. The control computer 110, the memory 112,the blanking control circuits 130, the deflection control circuits 132,the blanking amplifier 134, the digital-to-analog (DAC) amplifiers 136,a drive unit 137, the current detector 138, the stage positionmeasurement unit 139, and the storage device 140 are mutually connectedthrough a bus (not shown). Writing data is input into the storage device140 (storage unit) from the outside to be stored therein.

In the control computer 110, there are arranged a detection processingunit 50, a setting unit 51, a writing processing control unit 52, awriting data processing unit 54, a shifting width setting unit 56, alist generation unit 58, a dose calculation unit 60, and a dosecorrection unit 62. Each function, such as the detection processing unit50, the setting unit 51, the writing processing control unit 52, thewriting data processing unit 54, the shifting width setting unit 56, thelist generation unit 58, the dose calculation unit 60, and the dosecorrection unit 62 may be configured by hardware such as an electroniccircuit, or by software such as a program executing these functions.Alternatively, it may be configured by a combination of software andhardware. The data input and output to/from the detection processingunit 50, the setting unit 51, the writing processing control unit 52,the writing data processing unit 54, the shifting width setting unit 56,the list generation unit 58, the dose calculation unit 60, and the dosecorrection unit 62, and data being calculated are stored in the memory112 each time.

As described above, FIG. 1 shows a structure necessary for explainingEmbodiment 1. Other structure elements generally necessary for thewriting apparatus 100 may also be included.

FIGS. 2A and 2B are schematic diagrams each showing an example of theconfiguration of an aperture member according to Embodiment 1. In FIG.2A, holes (openings) 22 are formed in the shape of a matrix at apredetermined arrangement pitch in the aperture member 203, wherein m×n(m≧2, n≧2) holes 22 are arranged in m columns in the vertical direction(the y direction) and n rows in the horizontal direction (the xdirection). In FIG. 2A, holes 22 of 512 (rows)×8 (columns) are formed,for example. Each hole 22 has the same dimensional shape of aquadrangle. Alternatively, each hole maybe a circle of the samecircumference. In this case, there is shown an example of each rowhaving eight holes 22 from A to H in the x direction. Multi-beams 20 areformed by letting parts of an electron beam 200 respectively passthrough a corresponding hole of a plurality of holes 22. Here, there isshown the case where the holes 22 are arranged in two or more columnsand rows in both the x and the y directions, but it is not limitedthereto. For example, it is also acceptable to arrange a plurality ofholes 22 in only one row or in only one column, that is, in one rowwhere a plurality of holes are arranged as columns, or in one columnwhere a plurality of holes are arranged as rows. Moreover, the method ofarranging the holes 22 is not limited to the case of FIG. 2A where holesare aligned in a grid. It is also preferable to arrange the holes 22 asshown in FIG. 2B where the position of each hole in the second row isshifted from the position of each hole in the first row by a dimension“a” in the horizontal direction (x direction), for example. Similarly,it is also preferable to arrange the holes 22 such that the position ofeach hole in the third row is shifted from the position of each hole inthe second row by a dimension “b” in the horizontal direction (xdirection).

FIGS. 3A and 3B are schematic diagrams each showing a cross-sectionalstructure of a blanking plate according to Embodiment 1. The positionalrelation between the sections of FIGS. 3A and 3B is shifted from eachother by 90 degrees. FIG. 4A shows a part of the upper surface of ablanking plate and FIG. 4B shows a part of the under surface of theblanking plate according to Embodiment 1. FIG. 3A shows the sectionalong the arrow in FIG. 4A, seen from the direction of the lower part ofFIG. 4A. FIG. 3B shows the section along the arrow in FIG. 4B, seen fromthe direction of the right part of FIG. 4B. A passage hole (opening) isformed in the blanking plate 214, to be corresponding to the arrangementposition of each hole 22 of the aperture member 203. The blanker 212 isarranged at the upper surface side and the blanker 204 is arranged atthe under surface side of each passage hole of the blanking plate 214.

For example, as shown in FIGS. 3B and 4B, the blanker 204 on the undersurface is configured by two electrodes 24 and 26 being a pair. Theelectrode 26 at each passage hole is connected to the ground, and theelectrode 24 at each passage is connected to an individual blankingamplifier 134. For example, as shown in FIG. 4B, the beam 20 isdeflected toward the electrode 24 side (going downward in FIG. 4B) byapplying a positive voltage from the blanking amplifier 134. Since theelectrodes 24 and 26 are arranged on the under surface, the beam 20 isdifficult to collide with them, thereby reducing a failure risk. Theelectron beams 20 passing through the respective passage holes aredeflected by the voltage independently applied to the two electrodes 24and 26 being a pair, and blanking-controlled by such deflection. Thus,each of a plurality of blankers 204 performs blanking deflection of acorresponding beam 20 in the multiple beams having passed through aplurality of holes 22 (openings) of the aperture member 203.

On the other hand, for example, as shown in FIGS. 3A and 4A, the blanker212 on the upper surface is configured by two electrodes 25 and 27,being a pair, which are arranged in the direction orthogonal to thearrangement direction of the electrodes 24 and 26 of the blanker 204.For example, as shown in FIG. 4A, passage holes in the same column (forexample, in the y direction) in a plurality of passage holes formed inthe blanking plate 214 are configured by a pair of common electrodes 25and 27. However, it is also acceptable to configure a pair of twoelectrodes 25 and 27 for each passage hole, without using electrodes 25and 27 in common. Each electrode 25 is grounded and each electrode 27 isconnected to an individual relay circuit 122. Usually, the electrode 27is connected to the ground through the relay circuit 122. In this state,electron beams are not deflected. When cutting a defective beam, therelay is switched to the constant voltage source 120. For example, asshown in FIG. 4A, the electron beam is deflected toward the electrode 27side (going to the right from the left in FIG. 4A) by applying apositive voltage from the relay circuit 122. By virtue of thisconfiguration described above, the blanker 212 on the upper surface candeflect each beam 20 in the multiple beams, to be in the directionorthogonal to the deflection direction of the blanker 204 on the undersurface. Thereby, even when a blanking electrical potential of theblanker 204 on the under surface becomes unstable, it is possible tocertainly cut the beam 20 with deflection by the blanker 212 on theupper surface. Moreover, voltage is applied to each blanker 212 by theconstant voltage source 120, and the on/off operation of the voltage tobe applied is driven by the relay circuit 122 of a mechanical switchsystem. The mechanical switch of the relay circuit 122 is illustrated inFIG. 9. Compared with the blanking operation control system of theblanker 204 on the under surface which uses a semiconductor activeelement etc., by virtue of the simple structure of the blanker 212, afailure risk can be reduced and reliability can be achieved. A defectivebeam in the multiple beams having passed through a plurality of holes 22(openings) of the aperture member 203 is deflected to be in thedirection orthogonal to the deflection direction of a plurality ofblankers 204, by the blanker 212 at a corresponding position in aplurality of blankers 212. Moreover, since the blanker 212 on the uppersurface is used for cutting a defective beam as described later, itcontinuously 15 deflects a defective beam during writing. Therefore, theblanker 212 on the upper surface is not switched to be ON or OFF duringwriting, though the blanker 204 on the under surface is switched to ONor OFF. Thus, since the number of switching times is small, the risk offailure can be reduced.

The electron beam 200 emitted from the electron gun assembly 201(emission unit) almost perpendicularly illuminates the whole of theaperture member 203 by the illumination lens 202. A plurality of holes(openings), each in the shape of a quadrangle, are formed in theaperture member 203. The region including all the plurality of holes isirradiated by the electron beam 200. For example, a plurality ofquadrangular electron beams (multiple beams) 20 a to 20 e are formed byletting parts of the electron beam 200 irradiating the positions of aplurality of holes pass through a corresponding hole of the plurality ofholes of the aperture member 203 respectively. The multiple beams 20 ato 20 e respectively pass through corresponding blankers 212 and 204 ofthe blanking plate 214. The blanker 204 deflects (performs blankingdeflection) the electron beam 200 which passes respectively. Themultiple beams 20 a to 20 e having passed through the blanking plate 214are reduced by the reducing lens 205, and go toward the hole at thecenter of the limiting aperture member 206. Here, the electron beam 20which was deflected by the blanker 204 of the blanking plate 214deviates from the hole at the center of the limiting aperture member 206(blanking aperture member) and is blocked by the limiting aperturemember 206. On the other hand, the electron beam 20 which was notdeflected by the blanker 204 of the blanking plate 214 passes throughthe hole at the center of the limiting aperture member 206. Blankingcontrol is performed by on/off of the blanker 204 so as to controlon/off of the beam. Thus, the limiting aperture member 206 blocks eachbeam 20 which was deflected to be in the “beam off” state by a pluralityof blankers 204. Then, one shot beam is formed by beams which have beenformed during from the “beam on” state to the “beam off” state and havepassed through the limiting aperture member 206. The multi-beams 20having passed through the limiting aperture member 206 are focused bythe objective lens 207 to become a pattern image of a desired reductionratio, and respective beams (the entire multi-beams 20) having passedthrough the limiting aperture member 206 are collectively deflected inthe same direction by the deflector 208 so as to irradiate respectiveirradiation positions on the target object 101. While the XY stage 105is continuously moving, controlling is performed by the deflector 208 sothat irradiation positions of beams may follow the movement of the XYstage 105, for example. Ideally, multi-beams 20 to irradiate at a timeare aligned at pitches obtained by multiplying the arrangement pitch ofa plurality of holes of the aperture member 203 by a desired reductionratio described above. The writing apparatus 100 performs a writingoperation by the raster scan method which continuously irradiates shotbeams in order, and when writing a desired pattern, a required beam iscontrolled by blanking control to be “beam on” according to a pattern.

FIGS. 5A to 5C are schematic diagrams explaining a writing operationaccording to Embodiment 1. As shown in FIG. 5A, a writing region 30 ofthe target object 101 is virtually divided into a plurality ofstrip-shaped stripe regions 32 each having a predetermined width in they direction, for example. Each of the stripe regions 32 serves as awriting unit region. First, the XY stage 105 is moved and adjusted suchthat an irradiation region 34 to be irradiated by one-time irradiationof the multi-beams 20 is located at the left end of the first striperegion 32 or at a position more left than the left end, and then writingis started. When writing the first stripe region 32, the writingadvances relatively in the x direction by moving the XY stage 105 in the−x direction, for example. The XY stage 105 is continuously moved at apredetermined speed, for example. After writing the first stripe region32, the stage position is moved in the −y direction and adjusted suchthat the irradiation region 34 is located at the right end of the secondstripe region 32 or at a position more right than the right end, andlocated to be relatively in the y direction. Then, similarly, as shownin FIG. 5B, writing advances in the −x direction by moving the XY stage105 in the x direction, for example. Writing is performed whilealternately changing the direction, such as performing writing in the xdirection in the third stripe region 32, and in the −x direction in thefourth stripe region 32, and thus, the writing time can be reduced.However, the writing operation is not limited to the case of performingwriting while alternately changing the direction, and it is alsoacceptable to perform writing in the same direction when writing eachstripe region 32. By one shot, as shown in FIG. 5C, a plurality of shotpatterns 36 of the same number as the holes 22 are formed at a time bymultiple beams which have been formed by passing through respectivecorresponding holes 22 of the aperture member 203. For example, a beamwhich passed through one hole A of the aperture member 203 irradiatesthe position “A” shown in FIG. 5C and forms the shot pattern 36 at thisposition. Similarly, a beam which passed through one hole B of theaperture member 203 irradiates the position “B” shown in FIG. 5C andforms the shot pattern 36 at this position, for example. Hereafter, asimilar operation is performed with respect to C to H. Then, the rasterscan method is employed when writing each stripe 32, wherein while theXY stage 105 is moved in the x direction, the deflector 208 performsdeflection such that each shot moves (scans) in the y direction or inthe x and y directions in order and shot beam radiation is continuouslydelivered in order.

FIG. 6 is a flowchart showing main steps of a writing method accordingto Embodiment 1. In FIG. 6, the writing method according to Embodiment 1executes a series of steps: a defective beam detection step (S102), anunused beam setting step (S104), a shifting width setting step (S106), acoordinate list generation step (S108), a dose calculation step (S110),a dose correction step (S112), a writing step (S114), and a judgmentstep (S116).

In the defective beam detection step (S102), the detection processingunit 50 (detection unit) detects a defective beam in the multi-beams 20having passed through a plurality of holes 22 (openings) of the aperturemember 203, where the plurality of holes 22 are provided for forming themulti-beams 20 by the irradiation of the electron beam 200. Thedetection method is, for example, to measure a current amount of eachbeam of the multi-beams 20 by the detection processing unit 50.Specifically, the XY stage 105 is moved in order so that the Faraday cup106 may be located at the position irradiated by each beam of themulti-beams 20. The position of the XY stage 105 may be detected byletting a laser from the stage position measurement unit 139 irradiatethe mirror 210 and receiving a reflected light to perform detection. The

Faraday cup 106 is irradiated by each of the multi-beams 20 one by one,and an analog signal is sent to the current detector 138 from theFaraday cup 106. The current detector 138 outputs a digital signal (datasignal) indicating the amount of current of each beam irradiating theFaraday cup 106 to the detection processing unit 50. Thus, the detectionprocessing unit 50 measures a current amount of each beam irradiatingthe Faraday cup 106. It is preferable that beams other than the objectbeams to be measured are in the “beam off” state by a blanking control.Even if beams other than the measurement object beams irradiate theFaraday cup 106, it is acceptable for them to keep the “beam on” stateas long as they have a positional relation not to be detected by theFaraday cup 106. If there is a beam whose current amount cannot bemeasured (namely, current is not detected), the beam is a defective beamwhich is continuously “beam off” because the beam-on control is not ableto be performed. Moreover, if there is a beam which have an anomalouslysmall or fluctuating amount of current even though the current amount isdetected, the beam is a defective beam since a beam is imperfectly “beamon” and hence its dose cannot be controlled. On the other hand, if thereis a beam whose beam current amount is detected even though it iscontrolled to be “beam off” state, the beam is a defective beam which isalways continuously “beam on”. Thus, based on a data signal input fromthe current detector 138, the detection processing unit 50 detects abeam whose current amount cannot be measured (namely, current is notdetected) or whose current amount is anomalously small or fluctuating inspite of the beam-on control being set, as a defective beam, and detectsa beam whose beam current amount is detected in spite of the beam-offcontrol being set, as a defective beam.

In the unused beam setting step (S104), the setting unit 51 sets, asunused beams, beams formed by using a line of holes including a holethrough which a defective beam passes in a plurality of holes 22 of theaperture member 203.

FIG. 7 is a schematic diagram showing an unused beam according toEmbodiment 1. In FIG. 7, a region including all the holes 22 in thesixth column from the left, where a hole 23 through which a defectivebeam passes is included, is set as an unused beam partial region 40.

According to Embodiment 1, as described below, writing processing ishighly accurately performed even when a defective beam exists byperforming multiple writing while executing position shifting.

In the shifting width setting step (S106), the shifting width settingunit 56 sets a shifting width to be used when performing multiplewriting. According to Embodiment 1, multiple writing is performed whileshifting the position so that the position of a defective beam may notbe the same position, namely, may not overlap.

FIGS. 8A and 8B are schematic diagrams explaining a method of themultiple writing according to Embodiment 1. FIG. 8B shows one row in thecase where the sixth column in 512 (rows)×8 (columns) of the holes 22formed in the aperture member 203 is the unused beam partial region 40,as an example. FIG. 8A shows the case where multiple writing isperformed twice. Moreover, FIG. 8B shows an example where, in performingthe multiple writing, a shifting width d between the first writing (thefirst pass) and the second writing (the second pass) is set to be twocolumns of multi-beams.

In the coordinate list generation step (S108), the list generation unit58 generates a coordinate list of meshes located at a defective beam.Specifically, the list is generated as follows: When the beam of thesixth column is a defective beam, it indicates that the beam of thesixth column in the first pass is a defective beam. Therefore, theposition of the fourth column in the second pass is the same as that ofthe sixth column (defective beam) of the first pass. Moreover, the beamof the sixth column in the second pass is a defective beam. That is, theposition of the eighth column of the first pass is the same as that ofthe sixth column (defective beam) of the second pass. Then, the listgeneration unit 58 combines the irradiation position of the defectivebeam of each pass as illustrated in FIG. 8B to generate a coordinatelist 24 showing the irradiation position of the defective beam even ifthe position corresponds to the position of the defective beam onlyonce. That is, in the example of FIG. 8B, the positions of the sixthcolumn and the eighth column in the first pass are irradiation positionsof the defective beam in the coordinate list 24. Writing processing ishereafter started using this coordinate list 24. Although only one rowis described in this case, it is preferable to generate the coordinatelist 24 such that irradiation positions of a defective beam in theentire writing region are specifically descried in a mesh state.

In the dose calculation step (S110), the dose calculation unit 60calculates a dose required for each beam of each shot.

In the dose correction step (S112), the dose correction unit 62corrects, using the coordinate list 24, the dose of a beam irradiatingthe irradiation position of a defective beam in the coordinate list 24to be N/(N−1) times the dose. For example, when performing multiplewriting at multiplicity of N=2, the dose of a beam irradiating theirradiation position of a defective beam in the coordinate list 24 iscorrected to be twice the dose. In the example of FIG. 8B, the dose ofthe beam to irradiate the positions of the sixth column and the eighthcolumn of the first pass in the coordinate list 24 is corrected to betwice the dose.

In the writing step (S114), the writing processing control unit 52controls the relay circuit 122 to cut (block) the beam of a defectivebeam position (position corresponding to the unused beam partial region40) in the multiple beams formed by a plurality of holes 22 provided inthe aperture member 203. The relay circuit 122 applies the voltage fromthe constant voltage source 120 to a corresponding blanker 212 to driveit. Then, the blanker 212 performs deflection so that the beam of acorresponding defective beam position may be “beam off”. In the exampleof FIG. 8B, since the sixth column in the holes 22 of 512 (rows)×8(columns) is the unused beam partial region 40, deflection is performedsuch that the beam of the sixth column becomes “beam off”. The electronbeam 20 deflected by the blanker 212 shifts from the hole at the 30center of the limiting aperture member 206 (blanking aperture member)and is blocked by the limiting aperture member 206. The blanker 212continues to always cut the beam at the defective beam position duringthe writing operation.

Then, the writing data processing unit 54 controlled by the writingprocessing control unit 52 reads writing data from the storage device140, performs data conversion processing of a plurality of steps, andgenerates shot data unique to the apparatus, for each stripe region 32.The blanking control circuit 130 generates a signal for blanking controlof a shot performed by each blanker 204 for each of shot timings, basedon the shot data, and the signal is amplified by the blanking amplifier134 and converted from a digital to an analog signal to be output toeach blanker 204. It is not necessary to take a beam of a defective beamposition into consideration in particular. Since a beam of a defectivebeam position has already been cut by the blanker 212, it is possible tocut the beam even if controlled to be “beam on” by the blanker 204.

The deflection control circuit 132 calculates deflection amounts in thex and y directions of each shot, generates a signal for deflection.Then, the signal is amplified by the DAC amplifier 136 and convertedfrom a digital to an analog signal to be output to the deflector 208.

The writing unit 150 performs multiple writing while executing positionshifting so that the position of a defective beam may not be the sameposition, namely, may not overlap, by using at least one of theremaining multiple beams in the state where the defective beam has beencontrolled to be “beam off”. Specifically, the first pass is writtenfirst.

In the judgment step (S116), the writing processing control unit 52judges whether writing of multiple times has been performed or not, andwhen it is still necessary to perform writing for finishing the multipletimes writing, it returns to the dose calculation step (S110) to repeatfrom the dose calculation step (S110) to the judgment step (S116). Then,writing of the second pass is performed while executing positionshifting so that the position of a defective beam may not be the sameposition.

According to Embodiment 1, the dose which has not been used forirradiation because it is at the position of a defective beam is addedto the dose of other beam for multiple writing. In the example of FIGS.8A and 8B, since the irradiation dose of the beam to be delivered to thepositions of the sixth column and the eighth column in the first passhas already been corrected to be twice the dose, the beam dose of theeighth column of the first pass and the beam dose of the fourth columnof the second pass will irradiate the target object 101 as the doubleddose respectively. Therefore, the dose which was not delivered becauseof being a defective beam can be compensated.

As described above, according to Embodiment 1, it is possible to preventthe target object from being irradiated by a defective beam which iscontinuously “beam on” or whose dose cannot be controlled within apredetermined irradiation time period. Moreover, it is possible toperform writing without reducing the writing accuracy even when thereexists a defective beam. Further, it is possible to inhibit thereduction of throughput since beams other than the beam in one row wherea defective beam exists can be used. Furthermore, in performing multiplewriting, since an insufficient dose which was not delivered because ofbeing at a defective beam position can be compensated when performingwriting of other pass, additional pass writing becomes unnecessary andthroughput reduction can be inhibited.

Embodiment has been explained referring to concrete examples describedabove. However, the present invention is not limited to these specificexamples. Although the entire one row in which a defective beam existsis not used in the above example, it is also acceptable not to use onlya defective beam. Moreover, in the above example, although theirradiation dose which was not delivered because of being at a defectivebeam position is added to the dose of other beam used in multiplewriting without increasing the number of times of multiple writing, itis not limited thereto. Instead of adding the dose described above, itis also acceptable to further perform additional pass writing whichirradiates only an irradiation position of a defective beam. In theabove example, although the plurality of blankers 212 and the pluralityof blankers 204 are arranged on the same blanking plate 214, it is notlimited thereto. One of the plurality of blankers 212 and the pluralityof blankers 204 may be arranged on the blanking plate 214, another ofthe plurality of blankers 212 and the plurality of blankers 204 may bearranged on an another plate.

While the apparatus configuration, control method, etc. not directlynecessary for explaining the present invention are not described, someor all of them may be suitably selected and used when needed. Forexample, although description of the configuration of a control unit forcontrolling the writing apparatus 100 is omitted, it should beunderstood that some or all of the configuration of the control unit isto be selected and used appropriately when necessary.

In addition, any other multi charged particle beam writing apparatus anda method thereof that include elements of the present invention and thatcan be appropriately modified by those skilled in the art are includedwithin the scope of the present invention.

Additional advantages and modification will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

What is claimed is:
 1. A multi charged particle beam writing methodcomprising: detecting a defective beam in multiple beams having passedthrough a plurality of openings of an aperture member in which theplurality of openings are formed to form multiple beams by irradiationof a charged particle beam; and performing multiple writing whileexecuting position shifting such that positions of defective beams inthe multiple writing are not located at a same position, by using atleast one of remaining multiple beams in a state where the defectivebeam has been controlled to be beam off.
 2. The method according toclaim 1, further comprising: adding a dose which was not used forirradiation because of being at the position of the defective beam to adose of other beam used for multiple writing.
 3. The method according toclaim 1, further comprising: setting, as unused beams, beams formed byusing a line of openings including an opening through which a defectivebeam passes in the plurality of openings of the aperture member.
 4. Themethod according to claim 3, further comprising: setting a width ofshifting in performing multiple writing.
 5. The method according toclaim 4, further comprising: generating a coordinate list of mesheslocated at the defective beam.
 6. The method according to claim 5,further comprising: correcting, using the coordinate list, a dose of abeam irradiating an irradiation position of the defective beam in thecoordinate list to be multiplicity/(multiplicity−1) times the dose.